The veteran German artist Markus Lüpertz is an art-theft victim—again—after a bronze sculpture was stolen from his trusted foundry in Düsseldorf. It is the second time in only two years that works have been stolen from the renowned sculptor and painter. The 76-year-old artist was shocked to discover the theft last week.

Police continue to search for the stolen bronze, a brightly painted figure titled Athena. The sculpture is 2.3 meters high and weighs 230 kilos, and investigators are not ruling out that the perpetrators were interested in the bronze itself, rather than the work of art. “Both are possible,” a spokesperson for the Düsseldorf police told DPA on Sunday.

While the bronze would only bring a few thousand euros, the sculpture—of which there are several versions—has an estimated value of several hundred thousand euros. Robbing artist workshops for scrap material it is not uncommon. (Fellow German artist Anselm Kiefer had his French workshops broken into twice, and major pieces stolen for their iron and marble.)

How could the thieves make off with such a towering, colorful artwork? According to an eyewitness, two men were seen loading a large sculpture into a white van on Tuesday. On Thursday, the artist came to the foundry, which has been fabricating his bronze pieces for more than four decades, and was shocked to find out about the theft.

This is the second time Lüpertz has been the victim of theft. In 2015, burglars broke into his studio outside Berlin and made off with around 30 works on paper and sculptures. The artist appealed to the robbers over the media, and all but one work were returned to the studio within seven weeks of the robbery.